diff --git a/test-cases/RMLTC0000-SPARQL/mapping.ttl b/test-cases/RMLTC0000-SPARQL/mapping.ttl
index 32f54335..fc910499 100644
--- a/test-cases/RMLTC0000-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0000-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -9,7 +10,7 @@
             WHERE {
                 ?name a rdfs:Literal .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0001a-SPARQL/mapping.ttl b/test-cases/RMLTC0001a-SPARQL/mapping.ttl
index ce10acb5..879676f1 100644
--- a/test-cases/RMLTC0001a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0001a-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -10,7 +11,7 @@
             WHERE {
                 ?x foaf:name ?name .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0001b-SPARQL/mapping.ttl b/test-cases/RMLTC0001b-SPARQL/mapping.ttl
index ce10acb5..879676f1 100644
--- a/test-cases/RMLTC0001b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0001b-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -10,7 +11,7 @@
             WHERE {
                 ?x foaf:name ?name .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0002a-SPARQL/mapping.ttl b/test-cases/RMLTC0002a-SPARQL/mapping.ttl
index a4b3ca99..27651887 100644
--- a/test-cases/RMLTC0002a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0002a-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -13,7 +14,7 @@
                 ?x foaf:name ?Name ;
                    rdf:ID ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0002b-SPARQL/mapping.ttl b/test-cases/RMLTC0002b-SPARQL/mapping.ttl
index 996c2a94..e45c8b0e 100644
--- a/test-cases/RMLTC0002b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0002b-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -12,7 +13,7 @@
                 ?x foaf:name ?Name ;
                    rdf:ID ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0002g-SPARQL/mapping.ttl b/test-cases/RMLTC0002g-SPARQL/mapping.ttl
index 045abc3d..f25aae7a 100644
--- a/test-cases/RMLTC0002g-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0002g-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix ex: <http://example.com/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -12,7 +13,7 @@
                 ?x foaf:name ?Name ;
                    rdf:ID ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0002h-SPARQL/mapping.ttl b/test-cases/RMLTC0002h-SPARQL/mapping.ttl
index 65f55f23..df7c0e87 100644
--- a/test-cases/RMLTC0002h-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0002h-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix ex: <http://example.com/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -11,7 +12,7 @@
             WHERE {
                 ?x foaf:name ?Name ;
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0003c-SPARQL/mapping.ttl b/test-cases/RMLTC0003c-SPARQL/mapping.ttl
index 7594b83c..3e576f26 100644
--- a/test-cases/RMLTC0003c-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0003c-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -13,7 +14,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0004a-SPARQL/mapping.ttl b/test-cases/RMLTC0004a-SPARQL/mapping.ttl
index 1430217e..5053c863 100644
--- a/test-cases/RMLTC0004a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0004a-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@ ex:TriplesMap1 a rml:TriplesMap;
                 ?x  a <http://example.com/Student> ;
                     foaf:name  ?Student .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
@@ -43,7 +44,7 @@ ex:TriplesMap2 a rml:TriplesMap;
                         <http://example.com/plays> ?sportObject .
                     ?sportObject foaf:name ?Sport .
                 } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
diff --git a/test-cases/RMLTC0004b-SPARQL/mapping.ttl b/test-cases/RMLTC0004b-SPARQL/mapping.ttl
index 63907391..e425cb50 100644
--- a/test-cases/RMLTC0004b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0004b-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -13,7 +14,7 @@ ex:TriplesMap1 a rml:TriplesMap;
             WHERE {
                 ?x foaf:name ?Name .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
diff --git a/test-cases/RMLTC0006a-SPARQL/mapping.ttl b/test-cases/RMLTC0006a-SPARQL/mapping.ttl
index 856ae9f4..b6820692 100644
--- a/test-cases/RMLTC0006a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0006a-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix ex: <http://example.com/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -12,7 +13,7 @@ ex:TriplesMap1 a rml:TriplesMap;
             WHERE {
 
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
diff --git a/test-cases/RMLTC0007a-SPARQL/mapping.ttl b/test-cases/RMLTC0007a-SPARQL/mapping.ttl
index 0a6ecf8c..42b09838 100644
--- a/test-cases/RMLTC0007a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007a-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -14,7 +15,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007b-SPARQL/mapping.ttl b/test-cases/RMLTC0007b-SPARQL/mapping.ttl
index ce9dd3cb..77045f25 100644
--- a/test-cases/RMLTC0007b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007b-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -15,7 +16,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007c-SPARQL/mapping.ttl b/test-cases/RMLTC0007c-SPARQL/mapping.ttl
index add73be1..478c50f8 100644
--- a/test-cases/RMLTC0007c-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007c-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007d-SPARQL/mapping.ttl b/test-cases/RMLTC0007d-SPARQL/mapping.ttl
index 5ba11729..1cac4f47 100644
--- a/test-cases/RMLTC0007d-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007d-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -15,7 +16,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007e-SPARQL/mapping.ttl b/test-cases/RMLTC0007e-SPARQL/mapping.ttl
index 0d4cedea..4e362e6f 100644
--- a/test-cases/RMLTC0007e-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007e-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:subjectMap [
diff --git a/test-cases/RMLTC0007f-SPARQL/mapping.ttl b/test-cases/RMLTC0007f-SPARQL/mapping.ttl
index f9139a16..26318a46 100644
--- a/test-cases/RMLTC0007f-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007f-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -15,7 +16,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007g-SPARQL/mapping.ttl b/test-cases/RMLTC0007g-SPARQL/mapping.ttl
index dea5de56..09958b72 100644
--- a/test-cases/RMLTC0007g-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007g-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -13,7 +14,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0007h-SPARQL/mapping.ttl b/test-cases/RMLTC0007h-SPARQL/mapping.ttl
index 0a29b00f..e323fc9a 100644
--- a/test-cases/RMLTC0007h-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0007h-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -13,7 +14,7 @@
                     foaf:lastName  ?LastName ;
                     rdf:ID         ?ID .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0008a-SPARQL/mapping.ttl b/test-cases/RMLTC0008a-SPARQL/mapping.ttl
index 25634fd2..97d3504b 100644
--- a/test-cases/RMLTC0008a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0008a-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -16,7 +17,7 @@
                     <http://example.com/plays>  ?sportObject .
                 ?sportObject foaf:name ?Sport .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0008b-SPARQL/mapping.ttl b/test-cases/RMLTC0008b-SPARQL/mapping.ttl
index 731495fe..35ffb33c 100644
--- a/test-cases/RMLTC0008b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0008b-SPARQL/mapping.ttl
@@ -1,6 +1,7 @@
 @prefix activity: <http://example.com/activity/> .
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -16,7 +17,7 @@ ex:TriplesMap1 a rml:TriplesMap;
                 ?x  foaf:name ?Name ;
                     rdf:ID    ?ID ;
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
@@ -57,7 +58,7 @@ ex:TriplesMap2 a rml:TriplesMap;
                     ?x a <http://example.com/Sport> .
                     ?x foaf:name ?Sport .
                 } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>
diff --git a/test-cases/RMLTC0008c-SPARQL/mapping.ttl b/test-cases/RMLTC0008c-SPARQL/mapping.ttl
index 6663ebec..54f6196f 100644
--- a/test-cases/RMLTC0008c-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0008c-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@
                   ?x  foaf:name ?Name ;
                       rdf:ID    ?ID ;
               } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL>
diff --git a/test-cases/RMLTC0009a-SPARQL/mapping.ttl b/test-cases/RMLTC0009a-SPARQL/mapping.ttl
index d04651db..907d5e2a 100644
--- a/test-cases/RMLTC0009a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0009a-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -17,7 +18,7 @@
                   OPTIONAL { ?sportObject a <http://example.com/Sport> ;
                                             rdf:ID ?Sport . }
               } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL1>
@@ -61,7 +62,7 @@
                     ?x  foaf:name ?Name ;
                         rdf:ID    ?ID ;
                 } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL2>
diff --git a/test-cases/RMLTC0009b-SPARQL/mapping.ttl b/test-cases/RMLTC0009b-SPARQL/mapping.ttl
index d8bf179c..18ce4dc3 100644
--- a/test-cases/RMLTC0009b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0009b-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
@@ -17,7 +18,7 @@
                   OPTIONAL { ?sportObject a <http://example.com/Sport> ;
                                             rdf:ID ?Sport . }
               } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL1>
@@ -65,7 +66,7 @@
                     ?x  foaf:name ?Name ;
                         rdf:ID    ?ID ;
                 } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL2>
diff --git a/test-cases/RMLTC0012a-SPARQL/mapping.ttl b/test-cases/RMLTC0012a-SPARQL/mapping.ttl
index ca960969..65c6092f 100644
--- a/test-cases/RMLTC0012a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0012a-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@
                     foaf:lastName  ?lname ;
                     <http://example.com/amount> ?amount .
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source <http://example.com/base#InputSPARQL>
     ];
   rml:predicateObjectMap [
diff --git a/test-cases/RMLTC0012b-SPARQL/mapping.ttl b/test-cases/RMLTC0012b-SPARQL/mapping.ttl
index b754dcd1..f36eec4d 100644
--- a/test-cases/RMLTC0012b-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0012b-SPARQL/mapping.ttl
@@ -1,5 +1,6 @@
 @prefix ex: <http://example.com/> .
 @prefix foaf: <http://xmlns.com/foaf/0.1/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -14,7 +15,7 @@
                    ?x  foaf:firstName ?fname ;
                        foaf:lastName  ?lname ;
               } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL1>
@@ -44,7 +45,7 @@
                         foaf:lastName  ?lname ;
                         <http://example.com/city> ?city .
                 } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base/#InputSPARQL2>
diff --git a/test-cases/RMLTC0021a-SPARQL/mapping.ttl b/test-cases/RMLTC0021a-SPARQL/mapping.ttl
index ee72e5e0..5e44b45c 100644
--- a/test-cases/RMLTC0021a-SPARQL/mapping.ttl
+++ b/test-cases/RMLTC0021a-SPARQL/mapping.ttl
@@ -1,4 +1,5 @@
 @prefix ex: <http://example.com/> .
+@prefix formats: <http://www.w3.org/ns/formats/> .
 @prefix rml: <http://w3id.org/rml/> .
 @prefix sd: <http://www.w3.org/ns/sparql-service-description#> .
 
@@ -20,7 +21,7 @@ ex:TriplesMap1 a rml:TriplesMap;
                 ?x  foaf:name ?Name ;
                     rdf:ID    ?ID ;
             } """;
-      rml:referenceFormulation <https://www.w3.org/ns/formats/SPARQL_Results_JSON>;
+      rml:referenceFormulation formats:SPARQL_Results_JSON;
       rml:source [ a rml:RelativePathSource;
           rml:root rml:MappingDirectory;
           rml:path <http://example.com/base#InputSPARQL>